1. Field of the Invention
The present invention relates to a camera system, and particularly to one in which a functional switch is provided in the interchangeable lens. This lens switch can adequately set and control desired function or mode among many that are provided for the camera system.
2. Prior Art
Some camera systems are already disclosed in which one or more switches are provided in a lens to operate a function of the camera. In Japanese Laid-open Utility Model Publication No. 62310/1983, for example, the lens has a button switch to lock focusing. In another Japanese Laid-open Utility Model Publication No. 118423/1983, the lens has a push-switch that is operated in two strokes: the first shallow stroke locks the focusing and the second deep stroke releases the shutter. Further in Japanese Laid-open Patent Publication No. 140724/1983, the lens has two buttons: one is to lock the focusing, and the other is to change the Auto-Focusing (AF) mode between the One-shot AF and Continuous AF.
Each of these prior art lens switches, however, operates only one function of the camera. Since camera systems are growing more versatile, the lens should have many switches to control many camera functions. But it is not realistic to provide many switches in the lens because it is difficult for the photographer to correctly manipulate many lens switches during looking into the viewfinder.
Another problem about the lens switch is the conflict between the lens switch and the body switch over a camera function. For example in the case of the third prior art reference No. 140724/1983, the camera body also has a switch for changing the AF mode. Thus the problem is how to operate the AF function when the camera-body switch is ON but the lens switch is OFF, or vice versa.